1. Field of the Invention
The present invention relates to a semiconductor chip package, more particularly, in which a shielding conductive film is connected to a ground through a via hole, and a manufacturing method thereof.
2. Description of the Related Art
A high frequency module for use in a mobile telecommunication device such as a mobile phone is constructed of a high frequency circuit including a high frequency semiconductor device and a periphery circuit that are formed on a substrate thereof.
In general, current propagating in an electronic device induces electric field and magnetic field therearound, thereby generating a space due to electric potential difference. Here, the electric field changes with time and generates electric magnetic field therearound. That is, regardless of the induction of the device, current flows to create electromagnetic noise, which is an unnecessary energy.
Such electromagnetic noise, if transferred to other devices through a path, leads to degradation in performance and malfunction thereof.
To shield the electromagnetic noise and protect the semiconductor device, a shielding technique for forming a shielding film has been employed.
FIGS. 1a and 1b illustrate a shielding structure according to the prior art.
FIG. 1a is a cross-sectional view illustrating a high frequency module having a high frequency semiconductor device 12 on a substrate 11 shielded via a metal cap 13.
In the conventional shielding structure of the high frequency module shown in FIG. 1a, the metal cap 13, if reduced in its thickness, cannot remain strong but is easily warped, potentially contacting the high frequency device. To prevent short-circuit caused by contact between the metal cap 13 and the high frequency device, a certain space should be preserved under the metal cap 13 to accommodate the metal cap 13 that may be warped. For example, the metal cap should be formed to a thickness of 100 μm, and an inner space thereof should be designed to a thickness of 80 μm. This physical volume stands in the way of miniaturization of the high frequency module.
FIG. 1b is a cross-sectional view illustrating the high frequency module in which the shielding film is formed via a metal film 15 after resin molding.
In FIG. 1b, the high frequency semiconductor device 12 is mounted on the substrate 11 and resin molded to be hermetically sealed. Then the shielding film is formed on a surface of a mold 14 using the metal film 15.
This leads to smaller physical volume compared to a case where the metal cap is adopted. Yet, the metal film formed on the mold is not connected to a ground of the substrate, thus insignificant in terms of shielding effects.